Split mechanical seals are disclosed in U.S. Pat. Nos. 2,996,319; 3,025,070; and 3,578,345 all issued to applicant. Split mechanical seals are required to permit easy removal and replacement of the seal ring inserts which are rotatable relative to each other in order to maintain equipment and sealing integrity and reduce labor and maintenance costs in cases where unavoidable wear between such inserts requires frequent replacement.
In machines employed in plants and in various other usages as operative equipment, and most commonly in centrifugal pumps, it is necessary to provide a seal between a rotary member, such as a shaft, and a stationary member, such as a housing, or conversely, between a rotary housing, and the like, and a stationary shaft, stud, pipe, or similar round member. Such seals, although made of wear resistant material, and often specially treated to increase resistance to abrasion, wear, or corrosion, nevertheless in service will wear away or become corroded so that it is necessary at relatively frequent intervals to replace the parts which are in surface to surface contact upon relative rotation therebetween.
Frequently, and as a general proposition, such parts of annular shape, integrally formed and not interrupted or split, will require removal of surrounding and adjacent machine parts, at a great expenditure of time and labor, and with consequent excess monetary loss, before ample access room can be had to permit replacement. For instance, in a case where a shaft may extend from a housing, the exterior bearing or journal member for such a shaft or otherwise parts connected to the shaft, as a coupling, externally part of the housing, will have to be removed before such wear elements can be brought into access position for removal. During this period, the machine driven by the shaft is "down" or inoperative, and its product is lost during the interval of repair. Also, it takes considerable time to remove sufficient parts to obtain access space for replacement of the wear elements.
The solution to this problem has resided in providing opposed ring inserts in adjacent rotary and stationary parts of a seal assembly, so that the elements containing the inserts do not have to be split, with the resultant chance of leakage between the adjacent split segments, but rather the ring inserts are split, while being adapted to maintain firm contact between adjacent segments of the ring inserts.
Although the result provided by split ring inserts to the problem of effective mechanical seal with high efficiency of repair or replacement is adequate for most machines and usages, there still remain problems with service which is extremely abrasive, such as slurry pumps and the like used in the phosphate mining industry, and where highly effective sealing is required, such as in mining or hazardous materials solution handling.
It is therefore an object of this invention to provide a split mechanical seal assembly for more effective use in abrasive solution service. Another object is to provide a split mechanical seal assembly or more efficient sealing under difficult conditions. A further object of this invention provides a split mechanical seal assembly which is cost and labor efficient in repair or replacement of seal ring inserts. A still further object of this invention is to provide a split mechanical seal assembly which effectively maintains its seal under little or no hydraulic pressure or under high pressure. These and other objects are accomplished by this invention as will be observed from the following description.